Computer-generated sequence design for binary phase shift keying modulation data

ABSTRACT

Methods, systems, and devices for wireless communications are described. A device (e.g., a base station or a user equipment (UE)) may identify a sequence length corresponding to a number of resource blocks, and select a modulation scheme based on the sequence length. The device may select, from a set of sequences associated with the modulation scheme, a sequence having the sequence length. In some examples, the set of sequences may include at least one of a set of time domain phase shift keying computer-generated sequences or a set of frequency domain phase shift keying computer-generated sequences. The device may generate a reference signal for a data transmission based on the sequence and transmit the reference signal within the number of resource blocks.

CROSS REFERENCE

The present application for patent claims the benefit of GreeceProvisional Application No. 20180100499 by Yang, et al., entitled“Computer-Generated Sequence Design For a/2 Binary Phase Shift KeyingModulation Data,” filed Nov. 2, 2018, and to U.S. Provisional PatentApplication No. 62/791,581 by Yang, et al., entitled,“Computer-Generated Sequence Design For Binary Phase Shift KeyingModulation Data,” filed Jan. 11, 2019, and to U.S. ProvisionalApplication No. 62/794,534 by Yang, et al., entitled “Computer-GeneratedSequence Design For Binary Phase Shift Keying Modulation Data,” filedJan. 18, 2019, and to U.S. Provisional Application No. 62/822,480 byYang, et al., entitled “Computer-Generated Sequence Design For BinaryPhase Shift Keying Modulation Data,” filed Mar. 22, 2019, assigned tothe assignee hereof, and each of which is expressly incorporated byreference herein.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to computer-generated sequence design for

$\frac{\pi}{2}$binary phase shift keying (BPSK) modulation data.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

A base station may transmit a reference signal (e.g., a cell-specificreference signal) to a UE in wireless communications with the basestation. Alternatively, or additionally, the UE may transmit a referencesignal (e.g., a demodulation reference signal (DMRS)) to the basestation. The reference signal may provide the base station or the UEwith information for use in channel estimation. In some wirelesscommunications systems, such as in LTE-A wireless communicationssystems, the reference signal may be generated using a modulationscheme. Some wireless communications systems generate reference signalsfor certain sequence lengths that result in pilot tones transportingreference signals having a peak to average power ratio (PAPR) greaterthan pilot tones transporting the modulated data. As a result,generation of reference signals supporting certain sequence lengths andhaving certain power characteristics is desirable.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support improved computer-generated sequence designfor modulation, such as binary phase shift keying (BPSK) modulation.Generally, the described techniques provide for generating a referencesignal (e.g., using a sequence from a sequence table), where a length ofthe sequence may correspond to a number of allocated resource blockswithin which a data transmission and the reference signal are to betransmitted. A sequence may be a set of numbers (e.g., integer values),or a bit sequence (e.g., a binary sequence), an arithmetic sequence, ageometric sequence, etc. The reference signal and the data transmissionmay both have a peak to average power ratio (PAPR) that satisfies a PAPRthreshold, and the computer-generated sequence design for referencesignals may be suitable for use in New Radio (NR) systems and/or otherwireless communication systems. In some wireless communications systems,the reference signal may be generated using a certain modulation scheme(e.g., a phase shift keying (PSK), a quadrature phase shift keying(QPSK)) on a sequence (e.g., a Zadoff-Chu sequence). Although somewireless communications systems generate reference signals for certainsequence lengths that result in pilot tones transporting referencesignals having similar PAPR (e.g., a PAPR within a PAPR threshold)compared to pilot tones transporting modulated data, there are certainsequence lengths resulting in pilot tones transporting reference signalshaving a PAPR greater than pilot tones transporting the modulated data.Generating reference signals supporting certain sequence lengths andhaving certain characteristics is desirable.

A method of wireless communications is described. The method may includeidentifying a sequence length corresponding to a number of resourceblocks, selecting a modulation scheme based on the sequence length,selecting, from a set of sequences associated with the modulationscheme, a sequence having the sequence length, where the set ofsequences includes at least one of a set of time domain phase shiftkeying computer-generated sequences or a set of frequency domain phaseshift keying computer-generated sequences, generating a reference signalfor a data transmission based on the sequence, and transmitting thereference signal within the number of resource blocks.

An apparatus for wireless communications is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to identify asequence length corresponding to a number of resource blocks, select amodulation scheme based on the sequence length, select, from a set ofsequences associated with the modulation scheme, a sequence having thesequence length, where the set of sequences includes at least one of aset of time domain phase shift keying computer-generated sequences or aset of frequency domain phase shift keying computer-generated sequences,generate a reference signal for a data transmission based on thesequence, and transmit the reference signal within the number ofresource blocks.

Another apparatus for wireless communications is described. Theapparatus may include means for identifying a sequence lengthcorresponding to a number of resource blocks, selecting a modulationscheme based on the sequence length, selecting, from a set of sequencesassociated with the modulation scheme, a sequence having the sequencelength, where the set of sequences includes at least one of a set oftime domain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences,generating a reference signal for a data transmission based on thesequence, and transmitting the reference signal within the number ofresource blocks.

A non-transitory computer-readable medium storing code for wirelesscommunications is described. The code may include instructionsexecutable by a processor to identify a sequence length corresponding toa number of resource blocks, select a modulation scheme based on thesequence length, select, from a set of sequences associated with themodulation scheme, a sequence having the sequence length, where the setof sequences includes at least one of a set of time domain phase shiftkeying computer-generated sequences or a set of frequency domain phaseshift keying computer-generated sequences, generate a reference signalfor a data transmission based on the sequence, and transmit thereference signal within the number of resource blocks.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the modulation schemeincludes an 8 phase shift keying (8PSK) modulation scheme.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of time domain phaseshift keying computer-generated sequence includes time domain 8PSKsequences of length 6.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of time domain phaseshift keying computer-generated sequence includes at least one of timedomain 8PSK sequences of length 12, time domain 8PSK sequences of length18, or time domain 8PSK sequences of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of frequency domainphase shift keying computer-generated sequence includes at least one offrequency domain 8PSK sequences of length 6, frequency domain 8PSKsequences of length 12, frequency domain 8PSK sequences of length 18, orfrequency domain 8PSK sequences of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the data transmissionincludes a π/2 phase shift keying modulated data transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the data transmissionincludes at least one of a physical uplink shared channel (PUSCH)transmission, a physical uplink control channel (PUCCH) transmission, aphysical downlink shared channel (PDSCH) transmission, a physicaldownlink control channel (PDCCH) transmission, a physical sidelinkshared channel (PSSCH) transmission, or a physical sidelink controlchannel (PSCCH) transmission.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for modulating the datatransmission using π/2 binary phase shift keying (BPSK) modulation togenerate a π/2 BPSK modulated data transmission, and transmitting theπ/2 BPSK modulated data transmission within the number of resourceblocks, where a peak to average power ratio associated with the π/2 BPSKmodulated data transmission may be within a threshold of a peak toaverage power ratio associated with the reference signal.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for generating a set ofsequence tables that each include a set of sequences for a modulationscheme and for a different sequence length, where generating eachsequence of the set of sequences is based on the equation

${{x(k)} = e^{j\;{\varnothing{(k)}}\frac{\pi}{8}}},$where k is an integer value ranging from 0 to 5, and a sequence lengthof each sequence of the set of sequences is a length of 6, each numberin each sequence having an integer value selected from a set of integervalues including −7, −5, −3, −1, 1, 3, 5, and 7.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, one or more sequence tablesof the set of sequence tables includes sequences [−7−3 −7−3 7−5], [−7−31−5 −1−5], and [−7−3 3−3 −7−5].

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a set ofsequence tables that each include a set of sequences for a modulationscheme and for a different sequence length, and identifying, from theset of sequence tables, a sequence table including the set of sequencesassociated with the sequence length and the modulation scheme, whereselecting the sequence may be further based on identifying the sequencetable.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence table includesat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences corresponding to a certain sequencelength.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences is unique.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences satisfies a cyclic auto-correlation property.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences satisfies a cross-correlation property within the set ofsequences.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of sequences includesa level of correlation with a set of quadrature phase shift keying(QPSK) sequences.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a cross-correlation betweenthe set of sequences and the QPSK sequences is lower than a threshold,where the set of sequences is associated with a first radio accesstechnology and the QPSK sequences are associated with a second radioaccess technology different from the first radio access technology.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, selecting the bit sequencemay include operations, features, means, or instructions for selecting asequence that includes a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for modulating the sequenceusing the modulation scheme, where generating the reference signal forthe data transmission may be further based on the modulating.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the sequence length includesa sequence of length 6, a sequence of length 12, a sequence of length18, or a sequence of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the modulation schemeincludes at least one of an 8 phase shift keying (8PSK) modulationscheme, a 12 phase shift keying (12PSK) modulation scheme, or a π/4quadrature phase shift keying (π/4 QPSK) modulation scheme, or a QPSKmodulation scheme.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, selecting the modulationscheme may include operations, features, means, or instructions forselecting a first modulation scheme when the sequence length may be afirst value or selecting a second modulation scheme when sequence lengthmay be a second value.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first modulation schemeincludes an 8PSK sequence when the sequence length is a length of 6 andthe second modulation scheme includes a π/2 sequence when the sequencelength is greater than the length of 6.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, selecting the sequence mayinclude operations, features, means, or instructions for selecting atime-domain sequence when the sequence length may be a first value orselecting a frequency-domain sequence when the sequence length may be asecond value.

A method of wireless communications is described. The method may includeidentifying a sequence length corresponding to a number of resourceblocks based on a control message, where the sequence is from a set ofsequences including at least one of a set of time domain phase shiftkeying computer-generated sequences or a set of frequency domain phaseshift keying computer-generated sequences, receiving the referencesignal for a data transmission within the number of resource blocks,where the reference signal is generated based on a sequence having thesequence length, and demodulating the reference signal based on amodulation scheme associated with the sequence length.

An apparatus for wireless communications is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to identify asequence length corresponding to a number of resource blocks associatedwith a reference signal based on a control message, where the sequenceis from a set of sequences including at least one of a set of timedomain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences,receive the reference signal for a data transmission within the numberof resource blocks, where the reference signal is generated based on asequence having the sequence length, and demodulate the reference signalbased on a modulation scheme associated with the sequence length.

Another apparatus for wireless communications is described. Theapparatus may include means for identifying a sequence lengthcorresponding to a number of resource blocks associated with a referencesignal based on a control message, where the sequence is from a set ofsequences including at least one of a set of time domain phase shiftkeying computer-generated sequences or a set of frequency domain phaseshift keying computer-generated sequences, receiving the referencesignal for a data transmission within the number of resource blocks,where the reference signal is generated based on a sequence having thesequence length, and demodulating the reference signal based on amodulation scheme associated with the sequence length.

A non-transitory computer-readable medium storing code for wirelesscommunications is described. The code may include instructionsexecutable by a processor to identify a sequence length corresponding toa number of resource blocks associated with a reference signal based ona control message, where the sequence is from a set of sequencesincluding at least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences, receive the reference signal for adata transmission within the number of resource blocks, where thereference signal is generated based on a sequence having the sequencelength, and demodulate the reference signal based on a modulation schemeassociated with the sequence length.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the modulation schemeincludes an 8 phase shift keying (8PSK) modulation scheme.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of time domain phaseshift keying computer-generated sequence includes time domain 8PSKsequences of length 6.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of time domain phaseshift keying computer-generated sequence includes at least one of timedomain 8PSK sequences of length 12, time domain 8PSK sequences of length18, or time domain 8PSK sequences of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of frequency domainphase shift keying computer-generated sequence includes at least one offrequency domain 8PSK sequences of length 6, frequency domain 8PSKsequences of length 12, frequency domain 8PSK sequences of length 18, orfrequency domain 8PSK sequences of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the data transmissionincludes a π/2 binary phase shift keying modulated data transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the data transmissionincludes at least one of a PUSCH transmission, a PUCCH transmission, aPDSCH transmission, a PDCCH transmission, a PSSCH transmission, or aPSCCH transmission.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for demodulating the datatransmission using a π/2 binary phase shift keying modulation scheme togenerate a π/2 binary phase shift keying demodulated data transmission,where a peak to average power ratio associated with the π/2 binary phaseshift keying demodulated data transmission may be within a threshold ofa peak to average power ratio associated with the reference signal.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a set ofsequence tables that each include a set of sequences for a modulationscheme and for a different sequence length, and identifying, from theset of sequence tables, a sequence table including the set of sequencesassociated with the sequence length and the modulation scheme, wheredemodulating the reference signal may be further based on identifyingthe sequence table.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence table includesat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences corresponding to a certain sequencelength.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences is unique.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences satisfies a cyclic auto-correlation property.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each sequence in the set ofsequences satisfies a cross-correlation property within the set ofsequences.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of sequences includesa level of correlation with a set of QPSK sequences.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a cross-correlation betweenthe set of sequences and the QPSK sequences is lower than a threshold,where the set of sequences is associated with a first radio accesstechnology and the QPSK sequences are associated with a second radioaccess technology different from the first radio access technology.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, identifying the sequence mayinclude operations, features, means, or instructions for identifying asequence that includes a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the sequence length includesa sequence of length 6, a sequence of length 12, a sequence of length18, or a sequence of length 24.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the modulation schemeincludes at least one of an 8PSK modulation scheme, a 12PSK modulationscheme, or a π/4 QPSK modulation scheme, or a QPSK modulation scheme.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 illustrate examples of wireless communications systemsthat support computer-generated sequence design for

$\frac{\pi}{2}$binary phase shift keying (BPSK) modulation data in accordance withaspects of the present disclosure.

FIG. 3 illustrates an example of a constellation diagram that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIGS. 4 and 5 illustrate examples of transmit chains that support thatsupports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIGS. 6A through 6F illustrate examples of sequence tables that supportcomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIGS. 7 through 10 illustrate examples of sequence tables that supportcomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIGS. 11 and 12 show block diagrams of devices that supportcomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIG. 13 shows a block diagram of a communications manager that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIG. 14 shows a diagram of a system including a device that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

FIGS. 15 through 18 show flowcharts illustrating methods that supportcomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

A base station may allocate a number of resource blocks for a userequipment (UE) in wireless communications with the base station, atleast some of which may span a number of modulation symbols and/or anumber of sub-carriers. The number of resource blocks may be for areference signal transmission, a data transmission, or both. Forexample, either or both the base station and the UE may transmit areference signal (e.g., a cell-specific reference signal, a demodulationreference signal) for a data transmission, which may be a π/2 binaryphase shift keying (BPSK) modulated data transmission in some cases.Either or both the base station and the UE may identify a sequencelength corresponding to the number of resource blocks, and select amodulation scheme corresponding to the sequence length. For example, thesequence length may be a length of 6, a length of 12, a length of 18, ora length of 24. The base station or the UE may select a sequence (e.g.,having the sequence length) from a set of sequences (e.g., in a sequencetable) associated with the modulation scheme.

The set of sequences may include at least one of a set of time domainphase shift keying computer-generated sequences or a set of frequencydomain phase shift keying computer-generated sequences. For example, forsequence lengths of 6, the sequence table may correspond to time domain8PSK computer-generated sequences (e.g., the sequence table may includea set, such as a set of 30, of time domain 8PSK computer-generatedsequences). As such, the base station or the UE may use a time domain8PSK computer-generated sequence as the reference signal (e.g., for theπ/2 BPSK modulated data). The time domain 8PSK computer-generatedsequences may also apply to the other sequence lengths (e.g., sequencesof length 12, sequences of length 18, or sequences of length 24). Thebase station or the UE may alternatively use a sequence tablecorresponding to frequency domain 8PSK computer-generated sequences(e.g., the sequence table may include a set, such as a set of 30, offrequency domain 8PSK computer-generated sequences for differentsequence lengths (e.g., sequences of length 6, sequences of length 12,sequences of length 18, or sequences of length 24)). Accordingly, thesequence tables supporting different modulation schemes and having a setof time domain phase shift keying computer-generated sequences or a setof frequency domain phase shift keying computer-generated sequences, mayenable reference signal generation for data (e.g., π/2 BPSK modulateddata) having a desired peak to average power ratio (PAPR) (e.g., a lowPAPR or a PAPR that is within a PAPR threshold of a PAPR of the π/2 BPSKmodulated data).

Particular aspects of the subject matter described in this disclosuremay be implemented to realize one or more of the following potentialadvantages. The techniques employed by the described UEs may providebenefits and enhancements to the operation of the UEs. For example,operations performed by the UEs may provide improvements to wirelessoperations. In some examples, the UEs may support high reliability andlow latency wireless communications, among other examples, in accordancewith computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulated data. The described techniques may thus include featuresfor improvements to power consumption, spectral efficiency, higher datarates and, in some examples, may promote enhanced efficiency for highreliability and low latency operations, among other benefits.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are thendescribed in the context of a constellation diagram, a transmit chaindiagram, and a set of sequence tables that relate to computer-generatedsequence design for

$\frac{\pi}{2}$BPSK modulated data. Aspects of the disclosure are further illustratedby and described with reference to apparatus diagrams, system diagrams,and flowcharts that relate to computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulated data.

FIG. 1 illustrates an example of a wireless communications system 100that supports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation am in accordance with aspects of the present disclosure.The wireless communications system 100 includes base stations 105, UEs115, and a core network 130. In some examples, the wirelesscommunications system 100 may be a Long Term Evolution (LTE) network, anLTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR)network. In some cases, wireless communications system 100 may supportenhanced broadband communications, ultra-reliable (e.g., missioncritical) communications, low latency communications, or communicationswith low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130). The core network 130 may provide userauthentication, access authorization, tracking, Internet Protocol (IP)connectivity, and other access, routing, or mobility functions. The corenetwork 130 may be an evolved packet core (EPC), which may include atleast one mobility management entity (MME), at least one serving gateway(S-GW), and at least one Packet Data Network (PDN) gateway (P-GW). TheMME may manage non-access stratum (e.g., control plane) functions suchas mobility, authentication, and bearer management for UEs 115 served bybase stations 105 associated with the EPC. User IP packets may betransferred through the S-GW, which itself may be connected to the P-GW.The P-GW may provide IP address allocation as well as other functions.The P-GW may be connected to the network operators IP services. Theoperators IP services may include access to the Internet, Intranet(s),an IP Multimedia Subsystem (IMS), or a Packet-Switched (PS) StreamingService.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz. Wireless communications system 100 may also operate in asuper high frequency (SHF) region using frequency bands from 3 GHz to 30GHz, also known as the centimeter band. The SHF region includes bandssuch as the 5 GHz industrial, scientific, and medical (ISM) bands, whichmay be used opportunistically by devices that may be capable oftolerating interference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriersoperating in a licensed band (e.g., LAA). Operations in unlicensedspectrum may include downlink transmissions, uplink transmissions,peer-to-peer transmissions, or a combination of these. Duplexing inunlicensed spectrum may be based on frequency division duplexing (FDD),time division duplexing (TDD), or a combination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g. synchronization signals,reference signals, beam selection signals, or other control signals) maybe transmitted by a base station 105 multiple times in differentdirections, which may include a signal being transmitted according todifferent beamforming weight sets associated with different directionsof transmission. Transmissions in different beam directions may be usedto identify (e.g., by the base station 105 or a receiving device, suchas a UE 115) a beam direction for subsequent transmission and/orreception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (e.g., a direction associated with the receiving device,such as a UE 115). In some examples, the beam direction associated withtransmissions along a single beam direction may be determined based atleast in in part on a signal that was transmitted in different beamdirections. For example, a UE 115 may receive one or more of the signalstransmitted by the base station 105 in different directions, and the UE115 may report to the base station 105 an indication of the signal itreceived with a highest signal quality, or an otherwise acceptablesignal quality. Although these techniques are described with referenceto signals transmitted in one or more directions by a base station 105,a UE 115 may employ similar techniques for transmitting signals multipletimes in different directions (e.g., for identifying a beam directionfor subsequent transmission or reception by the UE 115), or transmittinga signal in a single direction (e.g., for transmitting data to areceiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer mayperform packet segmentation and reassembly to communicate over logicalchannels. A Medium Access Control (MAC) layer may perform priorityhandling and multiplexing of logical channels into transport channels.The MAC layer may also use hybrid automatic repeat request (HARQ) toprovide retransmission at the MAC layer to improve link efficiency. Inthe control plane, the Radio Resource Control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and a base station 105 or core network 130supporting radio bearers for user plane data. At the Physical layer,transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofTs=1/30,720,000 seconds. Time intervals of a communications resource maybe organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 Ts. The radio frames may be identified by a system framenumber (SFN) ranging from 0 to 1023. Each frame may include 10 subframesnumbered from 0 to 9, and each subframe may have a duration of 1 ms. Asubframe may be further divided into 2 slots each having a duration of0.5 ms, and each slot may contain 6 or 7 modulation symbol periods(e.g., depending on the length of the cyclic prefix prepended to eachsymbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an evolved universal mobiletelecommunication system terrestrial radio access (E-UTRA) absoluteradio frequency channel number (EARFCN)), and may be positionedaccording to a channel raster for discovery by UEs 115. Carriers may bedownlink or uplink (e.g., in an FDD mode), or be configured to carrydownlink and uplink communications (e.g., in a TDD mode). In someexamples, signal waveforms transmitted over a carrier may be made up ofmultiple sub-carriers (e.g., using multi-carrier modulation (MCM)techniques such as orthogonal frequency division multiplexing (OFDM) ordiscrete Fourier transform spread OFDM (DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth. Wireless communications system 100 may supportcommunication with a UE 115 on multiple cells or carriers, a featurewhich may be referred to as carrier aggregation or multi-carrieroperation. A UE 115 may be configured with multiple downlink componentcarriers and one or more uplink component carriers according to acarrier aggregation configuration. Carrier aggregation may be used withboth FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than othercomponent carriers, which may include use of a reduced symbol durationas compared with symbol durations of the other component carriers. Ashorter symbol duration may be associated with increased spacing betweenadjacent subcarriers. A device, such as a UE 115 or base station 105,utilizing eCCs may transmit wideband signals (e.g., according tofrequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) atreduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC mayconsist of one or multiple symbol periods. In some cases, the TTIduration (that is, the number of symbol periods in a TTI) may bevariable.

Wireless communications system 100 may be an NR system that may utilizeany combination of licensed, shared, and unlicensed spectrum bands,among others. The flexibility of eCC symbol duration and subcarrierspacing may allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

The base station 105 may perform a connection procedure (e.g., an RRCprocedure, such as a cell acquisition procedure, a random accessprocedure, an RRC connection establishment procedure, an RRCconfiguration procedure) with the UE 115. As part of the connectionprocedure, the base station 105 may allocate (schedule) time andfrequency resources for the UE 115. For example, the base station 105may allocate a number of resource blocks, each of which may span anumber of modulation symbols (e.g., OFDM symbols) and a number ofsub-carriers (e.g., 12 sub-carriers). In some examples, the number ofresource blocks may be for either or both a reference signaltransmission and a data transmission. For example, either or both thebase station 105 and the UE 115 may transmit a reference signal (e.g., acell-specific reference signal, a demodulation reference signal) for adata transmission, which may be a π/2 BPSK modulated data transmission.

Some wireless communications systems, for example, such as the wirelesscommunications system 100 may modulate the π/2 BPSK modulated datatransmission with DFT-s-OFDM and frequency domain spectral shaping(FDSS) to support cell edge UEs (e.g., UEs 115) to enhance cellcoverage. According to some techniques, either or both the base station105 and the UE 115 may select a sequence of a set of sequences specifiedin a set of sequence tables to generate a reference signal. For example,the base station 105 or the UE 115 may select a sequence for a givensequence length (e.g., sequences of length 24 or smaller) that is acomputer-generated frequency domain QPSK sequence (e.g., a sequencemodulated using a QPSK modulation scheme). These computer generatedfrequency domain QPSK sequences for reference signal generation,however, may result in a larger PAPR compared to data transmission thatare π/2 BPSK modulated.

According to another technique, either or both the base station 105 andthe UE 115 may select a sequence of a set of sequences specified inanother set of sequence tables to generate a reference signal. Thisalternative set of sequence tables may contain a computer-generated timedomain π/2 BPSK sequence for the reference signal generation for the π/2BPSK modulated data transmission. Although this alternative set ofsequence tables may facilitate generating reference signals for certainsequence lengths (e.g., sequences of length 12, sequence of length 18,or sequences of length 24) that result in pilot tones transportingreference signals having similar PAPR compared with pilot tonestransporting modulated π/2 BPSK data, there may be certain unsupportedsequence lengths (e.g., sequence of length 6) resulting in pilot tonestransporting reference signals having a PAPR larger than pilot tonestransporting the modulated π/2 BPSK data. According to the techniquesdescribed herein, either or both the base station 105 and the UE 115 maysupport a new set of sequence tables containing at least one of a set oftime domain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences. Eachsequence table may include, for example, sequences (e.g., 30 sequences)of a given length (e.g., sequences of length 6, sequences of length 12,sequences of length 18, or sequences of length 24).

Returning to the above example, either or both the base station 105 andthe UE 115 may identify a sequence length corresponding to the number ofresource blocks, and select a modulation scheme corresponding to thesequence length. For example, the sequence length may be a sequence oflength 6, a sequence of length 12, a sequence of length 18, or asequence of length 24. The base station 105 or the UE 115 may thenselect a sequence having the sequence length from a set of sequences ina sequence table associated with the modulation scheme. The set ofsequences may include a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences.

For example, for sequence length of 6, the sequence table may correspondto time domain 8PSK computer-generated sequences (e.g., the sequencetable may include a set of 30 time domain 8PSK computer-generatedsequences). As such, the base station 105 or the UE 115 may use a timedomain 8PSK computer-generated sequence as the reference signal for theπ/2 BPSK modulated data. The time domain 8PSK computer-generatedsequences may also apply to the other sequence lengths (e.g., sequencesof length 12, sequences of length 18, or sequence of length 24). Thebase station 105 or the UE 115 may alternatively use a sequence tablecorresponding to frequency domain 8PSK computer-generated sequences(e.g., the sequence table may include a set of 30 frequency domain 8PSKcomputer-generated sequences for different sequence lengths (e.g.,sequences of length 6, sequences of length 12, sequences of length 18,or sequences of length 24)). Alternatively, the base station 105 may usea time domain π/2 phase shift keying computer-generated sequence as thereference signal for the π/2 BPSK modulated data.

By supporting a sequence table for different modulation schemes andhaving a set of time domain phase shift keying computer-generatedsequences or a set of frequency domain phase shift keyingcomputer-generated sequences, may result in each sequence of the sethaving a PAPR that is within a PAPR threshold from a PAPR of themodulated π/2 BPSK data. Some benefits of the techniques describedherein may include improved efficiency and reduced latency in thewireless communications system 100.

FIG. 2 illustrates an example of a wireless communications system 200that supports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The wireless communications system 200 may include a basestation 105-a and a UE 115-a, which may be examples of the correspondingdevices described with reference to FIG. 1. In some examples, thewireless communications system 200 may implement aspects of the wirelesscommunications system 100. For example, the base station 105-a and theUE 115-a may support a set of sequence tables related to varioussequence lengths and different modulation schemes. Each sequence tablemay include either or both a set of time domain phase shift keyingcomputer-generated sequences and a set of frequency domain phase shiftkeying computer-generated sequences, which may enable reference signaltransmission and data transmission having a desired PAPR (e.g., a lowPAPR or a PAPR that is less than a PAPR threshold).

The base station 105-a may perform a connection procedure (e.g., an RRCprocedure, such as a cell acquisition procedure, a random accessprocedure, an RRC connection establishment procedure, an RRCconfiguration procedure) with the UE 115-a. The base station 105-a maybe configured with multiple antennas, which may be used for directionalor beamformed transmissions. As part of the connection procedure, thebase station 105-a may establish a bidirectional communication link 225for communication with the UE 115-a. In some examples, following theconnection procedure, the base station 105-a may allocate time andfrequency resources for the UE 115-a. For example, the base station 105may allocate a number of resource blocks related to a system bandwidth,each resource block may span a number of modulation symbols and a numberof sub-carriers.

The number of resource blocks may be for either or both a referencesignal transmission and a data transmission. For example, the basestation 105-a may allocate a subset of the resource blocks for carryinga reference signal 215 and another subset of the resource blocks for adata transmission 220 (e.g., for downlink transmission to the UE 115-a).In some aspects, the data transmission 220 may include a physicaldownlink shared channel (PDSCH) transmission or a physical downlinkcontrol channel (PDCCH) transmission. In an example, the base station105-a may communicate the data transmission 220 to the UE 115-a, wherethe data transmission 220 includes a PDSCH transmission or a PDCCHtransmission.

Additionally, or alternatively, the UE 115-a may use the subset of theresource blocks for carrying the reference signal 215 and a secondsubset of the resource blocks for the data transmission 220 (e.g.,uplink transmission from the UE 115-a to the base station 105-a). Insome aspects, the data transmission 220 may include a physical uplinkshared channel (PUSCH) transmission or a physical uplink control channel(PUCCH) transmission. In an example, the UE 115-a may communicate thedata transmission 220 to the base station 105-a, where the datatransmission 220 includes a PUSCH transmission or a PUCCH transmission.In some aspects, the data transmission 220 may include a physicalsidelink shared channel (PSSCH) transmission or a physical sidelinkcontrol channel (PSCCH) transmission. For example, the UE 115-a maycommunicate the data transmission 220 to another UE 115, where the datatransmission 220 includes a PSSCH transmission or a PSCCH transmission.In some examples, the resource block allocation may include a smallnumber of resource blocks, for example including two, three, or fourresource blocks, or any number of resource blocks less than or equal toa threshold number of resource blocks (e.g., satisfying a resource blockthreshold) for supporting computer-generated sequences for smallresource blocks for π/2 BPSK modulation.

To generate the reference signal 215, the base station 105-a mayidentify a sequence length (e.g., a sequence of length 6, a sequence oflength 12, a sequence of length 18, or a sequence of length 24)corresponding to the number of allocated resource blocks. For example,the sequence length may be a function of or associated with the numberof allocated resource blocks. The function or association may be a fixedrelationship between the number of resource blocks and the sequencelength. For example, if the number of allocated resource blocks is oneor two resource blocks, the sequence length may be 12. In anotherexample, if the number of allocated resource blocks is three resourceblocks, the sequence length may be 18. In a further example, if thenumber of allocated resource blocks is four resource blocks, thesequence length may be 24. If the number of allocated resource blocks ismore than a defined number of resource blocks (e.g., more than 4resource blocks), the sequence length for the reference signalgeneration may be 24, or other techniques may be used for generating thereference signal.

The base station 105-a may provide an indication of the number ofallocated resource blocks to the UE 115-a. For example, the base station105-a may transmit a message (e.g., downlink control information)carrying the indication of the number of allocated resource blocks. Insome examples, the message may include a sequence length of a sequenceused to generate the reference signal 215. The base station 105-a mayidentify and/or select a modulation scheme according to the sequencelength. For example, the modulation scheme may include an 8 phase shiftkeying (8PSK) modulation scheme, a 12 phase shift keying (12PSK)modulation scheme, or a

$\frac{\pi}{4}$quadrature phase shift keying

$\left( {\frac{\pi}{4}\mspace{14mu}{QPSK}} \right),$among others.

Upon identifying and/or selecting the modulation scheme to use for thegiven sequence length, the base station 105-a may identify, from a setof sequence tables (for example, see FIGS. 6 through 10), a sequencetable including a set of sequences associated with the sequence lengthand the modulation scheme. Additionally, or alternatively, the UE 115-amay identify, from the set of sequence tables, a sequence tableincluding a set of sequences associated with the sequence length and themodulation scheme. Each sequence table from the set of sequence tablesmay include a set of sequences for a modulation scheme and for adifferent sequence length. For example, each sequence table may includeat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences corresponding to at least one of acertain sequence length and a modulation scheme. In some examples, theset of time domain phase shift keying computer-generated sequence mayinclude time domain 8BPSK sequences of length 6. Additionally, oralternatively, the set of frequency domain phase shift keyingcomputer-generated sequences may include at least one of frequencydomain 8BPSK sequences of length 6, frequency domain 8BPSK sequences oflength 12, frequency domain 8BPSK sequences of length 18, or frequencydomain 8BPSK sequences of length 24.

Either or both the base station 105-a and the UE 115-a may in some casesuse different modulation schemes for different sequence lengths. In someexamples, the base station 105-a and the UE 115-a may use one modulationscheme for a first sequence having a first length L1, and use adifferent modulation scheme for a second sequence having a length L2.For example, the base station 105-a and the UE 115-a may use an 8PSKmodulation for a sequence of length 6, and use π/2 BPSK modulation forsequences of lengths 12, 18, 24. Alternatively, the base station 105-aand the UE 115-a may use an 8PSK modulation for sequences of length 6,12, 18, and 24.

In some examples, either or both the base station 105-a and the UE 115-amay select a given sequence based on the sequence length. For example,the base station 105-a and the UE 115-a may select time-domain sequencesfor a first length L1 and use frequency-domain sequences for a secondlength L2. For instance, the base station 105-a and the UE 115-a may usetime domain

$\frac{\pi}{2}$BPSK sequences for sequence lengths of 12, and use frequency domain 8PSKsequences for sequence lengths of 6, 18, or 24, or a combinationthereof. Alternatively, the base station 105-a and the UE 115-a may usetime domain

$\frac{\pi}{2}$BPSK sequences for sequence lengths of 6, 12, 18, or 24, or acombination thereof, or use frequency domain 8PSK sequences for sequencelengths of 6, 12, 18, or 24, or a combination thereof.

In some examples, either or both the base station 105-a and the UE 115-amay be preconfigured with the set of sequence tables (for example, seeFIGS. 6 through 10). Each sequence table may be configured, for example,according to a set of criteria to enable reference signal transmissionand data transmission having a desired PAPR determined with FDSS (e.g.,a low PAPR or a PAPR that is less than a PAPR threshold). The PAPR maybe determined assuming a particular FDSS that corresponds to a timedomain filter (e.g., of [−0.26, 0.93, −0.26]). Alternatively, either orboth the base station 105-a and the UE 115-a may generate the set ofsequence tables (for example, see FIGS. 6 through 10), according to theset of criteria.

An example criteria may include that each sequence in the set ofsequences is unique (e.g., nonduplicative). An 8PSK sequence may bedefined by the following equation

$\begin{matrix}{{x(k)} = e^{j\;{\varnothing{(k)}}\;\frac{\pi}{8}}} & (1)\end{matrix}$where k=0, 1, 2, 3, . . . N−1, where N may be an integer that denotes alength of the sequence. At least two time domain sequences x₁ and x₂ maybe equivalent (e.g., nonunique, duplicative) if x₂ can be obtained fromx₁ by applying a cyclic shift to x₁ and multiplying each element of x₁by a constant phase rotation φ, which may be defined by the followingset:

$\varphi \in {\left\{ {0,\frac{\pi}{4},{2\;\frac{\pi}{4}},\frac{3\;\pi}{4},\pi,\frac{5\;\pi}{4},\frac{6\;\pi}{4},\frac{7\;\pi}{m}} \right\}.}$For example, the following sequences are equivalent and a result ofapplying a cyclic shift to a sequence ϕ₁=[−7 5 1 5−7 −3], ϕ₂=[1 5−7 −3−75] by cyclicly-shifting x₁ by x₂, and ϕ₃=[3 7 −5 −1 −5 7] that is

${x_{3} = {e^{j\;\frac{\pi}{4}} \cdot x_{2}}},$where the multiplication may be performed for each element of thesequence x₂. In contrast to the time domain, at least two frequencydomain sequences x₁ and x₂ may be equivalent (e.g., nonunique,duplicative) if x₂ can be obtained from x₁ by multiplying each elementof x₁ by the constant phase rotation φ, and then multiplying theresulting sequence point-wise by a phase sequence from the following setof phase sequences:

${\omega_{1} = \left\lbrack {0,0,\ldots}\mspace{14mu} \right\rbrack},{\omega_{2} = \left\lbrack {0,\frac{\pi}{2},\pi,\frac{3\pi}{2},\ldots}\mspace{11mu} \right\rbrack},{\omega_{3} = \left\lbrack {0,\pi,{2\;\pi},{3\pi},\ldots}\mspace{11mu} \right\rbrack},{\omega_{4} = {\left\lbrack {0,\frac{3\;\pi}{2},{3\;\pi},\frac{9\;\pi}{2},\ldots}\mspace{11mu} \right\rbrack.}}$For example, two frequency domain sequences of length 6 such as, x and ymay be equivalent if their elements x(k) and y(k) satisfy the followingexpression:x(k)=e ^(jw) ³ ^((k)) ·y(k)  (2)where k=0, 1, 2, 3, . . . 5.

Another example criteria may include that each sequence in the set ofsequences of a sequence table satisfies a cyclic auto-correlationproperty. In some examples, there may be a small cyclic auto-correlationproperty for at least three tabs. The auto-correlation property for asequence having delays d=−2, −1, 1, and 2 may be given by the followingequation:Σ_(0≤n≤5) x(n)conj(x(n+d))≤√{square root over (2)}  (3)where L is a number of symbols in a sequence (e.g., L=6, 12, 18, or 24)and indices n are interpreted as mod(L) (e.g., cyclic). For example, ifL=6 and n=6, then 6 mod 6=0, and hence x(6)=x(0). In further examples, acriteria may include that each sequence in the set of sequencessatisfies a cross-correlation property within the set of sequences, orhas a level of correlation with a set of QPSK sequences to enablecoexistence with other wireless communications systems (e.g., QPSKsequences of length 6 in LTE-A wireless communications systems).

The base station 105-a may select a sequence from a given sequence table(for example, see FIGS. 6 through 10), and generate the reference signal215 for the data transmission 220 (e.g., a data transmission (e.g., π/2BPSK modulated data transmission)). For example, the base station 105-amay modulate the selected sequence to using the modulation scheme togenerate the reference signal 215. In some examples, the base station105-a may modulate the data transmission 220 using a π/2 BPSK modulationscheme to generate a π/2 BPSK modulated data transmission, and transmitthe modulated π/2 BPSK data transmission within the number of allocatedresource blocks. In some examples, the base station 105-a may include inthe message an indication (e.g., an index value) for the sequence tableused from the set of sequence tables to generate the reference signal.Although the above example for generating the reference signal 215 forthe data transmission (e.g., π/2 BPSK modulated data transmission) aregenerally explained from the base station 105-a perspective, the UE115-a may perform the same or similar operations to generate thereference signal 215 for the data transmission 220, as well as the datatransmission 220 itself. In some examples, the UE 115-a may modulate thedata transmission 220 using a π/2 BPSK modulation scheme to generate aπ/2 BPSK modulated data transmission, and transmit the modulated π/2BPSK data transmission within the number of allocated resource blocks.

The UE 115-a may receive the message from the base station 105-a, andidentify the indication of the number of resource blocks associated withthe reference signal 215. The UE 115—may identify the sequence lengthcorresponding to the number of resource blocks, and receive thereference signal 215 for the data transmission 220 within the number ofresource blocks. For example, the UE 115-a may demodulate the referencesignal 215 based on a modulation scheme associated with the sequencelength. In some examples, the UE 115-a may receive and demodulate thedata transmission 220 using the modulation scheme to generate a π/2 BPSKdemodulated data transmission, where a PAPR associated with the π/2 BPSKdemodulated data transmission is within a threshold of a PAPR associatedwith the reference signal 215. Although the above example for receivingthe reference signal 215 for the data transmission (e.g., π/2 BPSKmodulated data) are generally explained from the UE 115-a perspective,the base station 105-a may perform the same or similar operations toreceive and demodulate the reference signal 215 for the datatransmission 220, as well as the data transmission 220 itself.

Accordingly, either or both the bases station 105-a and UE 115-a maysupport using sequence information (e.g., sequence tables) for differentmodulation schemes and having a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences, which may result in each sequenceof the set having a PAPR that is within a PAPR threshold from a PAPR ofthe modulated π/2 BPSK data. Some benefits of the techniques describedherein may include improved efficiency and reduced latency in thewireless communications system 200.

FIG. 3 illustrates an example of a constellation diagram 300 thatsupports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The constellation diagram 300 may implement aspects of thewireless communications systems 100 and 200. For example, with referenceto FIG. 2, either or both the base station 105-a and the UE 115-a maymodulate a sequence onto a carrier signal. In some examples, either orboth the base station 105-a and the UE 115-a may apply a modulationscheme (e.g., 8PSK modulation scheme) related to the constellationdiagram 300, which receives an incoming sequence and transmits themodulated sequence using a signal that can have eight different possiblestates, which are known as symbols 305. Each symbol may be described byan amplitude value and an initial phase value. According to theconstellation diagram 300 for a given sequence (e.g., 8PSK sequence) theeight different possible states may be found by the followingexpression:

$\begin{matrix}{x = e^{j\;\phi\frac{\pi}{8}}} & (4)\end{matrix}$where j=√{square root over (−1)}, π=3.1415926 . . . , and ϕ∈{−7, −5, −3,−1, 1, 3, 5, 7}. In some examples, to represent the 8PSK sequence, itmay be sufficient to prove the phase index ϕ of the constellation. Forexample, the following integer tuple {-7, −5, −3, −1, 1, 3, 5, 7}represent the 8PSK sequences

$\left\lbrack {e^{\frac{{- j}\; 7\pi}{8}},e^{\frac{{- j}\; 5\pi}{8}},e^{\frac{{- j}\; 3\pi}{8}},e^{\frac{{- j}\;\pi}{8}},e^{\frac{j\;\pi}{8}},e^{\frac{j\; 3\pi}{8}},e^{\frac{j\; 5\pi}{8}},e^{\frac{j\; 7\pi}{8}}} \right\rbrack.$

FIG. 4 illustrates an example of a transmit chain 400 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The transmit chain 400 may correspond to sequences in timedomain. The output of the transmit chain 400 may include a referencesignal. In some examples, the transmit chain 400 may implement aspectsof the wireless communications systems 100 and 200. For example, withreference to FIG. 2, either or both the base station 105-a and the UE115-a may include a component of the transmit chain 400. In someexamples, either or both the base station 105-a and the UE 115-a, mayidentify a sequence length corresponding to a number of resource blocksand select from a set of sequences associated with a modulation scheme,a phase sequence ϕ having the sequence length. The set of sequences mayinclude a set of time domain phase shift keying computer-generatedsequences. To generate the reference signal 215, the phase sequence ϕmay be provided to a modulator 405 that may apply 8PSK modulation to thephase sequence ϕ. The modulator 405 may 8PSK-modulate each bit in thesequence b, and output a modulated sequence x to a discrete Fouriertransform (DFT) component 410. Alternatively, the modulator 405 may12PSK-modulate or

$\frac{\pi}{4}$QPSK modulate each bit in the phase sequence ϕ.

The DFT component 410 may apply a DFT operation to the modulatedsequence x (e.g., time domain data) to generate frequency domain data Xthat is output to an FDSS component 415. In some examples, the FDSScomponent 415 may be an optional action in the transmit chain 400. TheFDSS component 415 may perform an FDSS operation on the frequency domaindata X to generate spectrally shaped frequency domain data Y. In someexamples, FDSS may be a pulse-shaping filtering process implemented inthe frequency domain by element-wise multiplication of the frequencydomain data X and a bandwidth of the number of allocated resource blocks(e.g., a filter of bandwidth equal to the number of allocated resourceblocks). In some cases, 8PSK modulation with FDSS may result in very lowPAPR.

A tone mapper 420 may map the spectrally shaped data Y onto respectiveresource elements of the number of allocated resource blocks byselecting which subcarriers (e.g., tones) of a carrier are torespectively transport portions of the spectrally shaped data Y. Usingthe mapping, an inverse fast Fourier transform (IFFT) component 425 mayperform an IFFT (or, equivalently, an inverse discrete Fourier Transform(IDFT)) on the spectrally shaped data to generate a time domainwaveform. For example, the IFFT component 425 may mix the spectrallyshaped data Y with respective subcarriers based on the mapping togenerate a set of sinusoids, and sum the sinusoids to generate the timedomain waveform. In some cases, a prefix adder 430 may add a cyclicprefix (CP) to the time domain waveform. The CP may be a set of samplesthat may be duplicated from the end of a transmitted symbol and appended(e.g., cyclically) to the beginning of the symbol. A mixer may modulatethe output from the prefix adder 430 to radio frequency for transmissionof a DFT-S-OFDM waveform by an antenna of either the base station 105-aor the UE 115-a via a wireless channel. In some examples, the output maybe a reference signal that is generated based at least in part on thephase sequence ϕ.

FIG. 5 illustrates an example of a transmit chain 500 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The transmit chain 500 may correspond to sequences infrequency domain. The output of the transmit chain 500 may include areference signal. In some examples, the transmit chain 500 may implementaspects of the wireless communications systems 100 and 200. For example,with reference to FIG. 2, either or both the base station 105-a and theUE 115-a may include a component of the transmit chain 500. In someexamples, either or both the base station 105-a and the UE 115-a, mayidentify a sequence length corresponding to a number of resource blocksand select from a set of sequences associated with a modulation scheme,a frequency domain phase sequence ϕ having the sequence length. The setof sequences may include a set of frequency domain phase shift keyingcomputer-generated sequences. To generate the reference signal 215, thefrequency domain phase sequence ϕ may be provided to a modulator 505that may apply 8PSK modulation to the frequency domain phase sequence ϕ.Alternatively, the modulator 505 may 12PSK-modulate or

$\frac{\pi}{4}$QPSK-modulate each bit in the phase sequence ϕ.

The modulator 505 may 8PSK-modulate each bit in the frequency domainphase sequence ϕ, and output a modulated sequence X to an FDSS component510. In some examples, the FDSS component 510 may be an optional featurein the transmit chain 500. The FDSS component 510 may perform an FDSSoperation on the frequency domain data X to generate spectrally shapedfrequency domain data Y. In some examples, FDSS may be a pulse-shapingfiltering process implemented in the frequency domain by element-wisemultiplication of the frequency domain data X and a bandwidth of thenumber of allocated resource blocks. In some cases, 8PSK modulation withFDSS may result in very low PAPR. For example, an 8PSK sequence withFDSS may result in very low PAPR, where the selection of the 8PSKsequence may be according to the techniques described herein.

A tone mapper 515 may map the spectrally shaped data Y onto respectiveresource elements of the number of allocated resource blocks byselecting which subcarriers (e.g., tones) of a carrier are torespectively transport portions of the spectrally shaped data Y. Usingthe mapping, an IFFT component 520 may perform an IFFT (or,equivalently, an IDFT) on the spectrally shaped data to generate a timedomain waveform. For example, the IFFT component 520 may mix thespectrally shaped data Y with respective subcarriers based on themapping to generate a set of sinusoids, and sum the sinusoids togenerate the time domain waveform. In some cases, a prefix adder 525 mayadd a CP to the time domain waveform. The CP may be a set of samplesthat may be duplicated from the end of a transmitted symbol and appended(e.g., cyclically) to the beginning of the symbol. A mixer may modulatethe output from the prefix adder 525 to radio frequency for transmissionof a DFT-S-OFDM waveform by an antenna of either the base station 105-aor the UE 115-a via a wireless channel. In some examples, the output maybe a reference signal that is generated based at least in part on thephase sequence ϕ.

FIG. 6A illustrates an example of a sequence table 600-a that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-a may beimplemented by one or more devices in accordance with aspects of thewireless communications systems 100 and 200. For example, the sequencetable 600-a may correspond to time domain sequences of length 6. In someexamples, a time domain sequence of length 6 in the sequence table 600-amay be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 600-a may include a set of sequences 610-a, each ofwhich may have a length (e.g., a length of 6). Each sequence 610-a maycorrespond to a particular index value of index 605-a in the sequencetable 600-a. In the sequence table 600-a, the index values may rangefrom a first value (e.g., 0) to a second value (e.g., 29). Withreference to FIG. 2, the base station 105-a may inform the UE 115-a ofan index value corresponding to a sequence to use for generation of thereference signal 215. The sequence may be defined by the followingexpression in some cases:

${{x(n)} = e^{\frac{j\;{\phi{(n)}}}{8}}},$where n=0, 1, . . . 5, and 0 corresponds to at least one of thesequences in the set of sequences 610-a. For example, an index value of“1,” for example, may correspond to a sequence of [−7 −3 1 −3 7 −5] inthe sequence table 600-a. The sequence [−7 −3 1 −3 7 −5] may correspondto the following 8PSK sequence of length 6

$\left\lbrack {e^{- \frac{j\; 7\pi}{8}},e^{- \frac{j\; 3\pi}{8}},e^{\frac{j\;\pi}{8}},e^{- \frac{j\; 3\pi}{8}},e^{\frac{j\; 7\pi}{8}},e^{- \frac{j\; 5\pi}{8}}} \right\rbrack.$The sequence table 600-a may satisfy one or more of criteria (e.g. asdescribed in FIG. 2). For example, each sequence in the set of sequences610-a may be unique, or satisfy a cyclic auto-correlation property, orsatisfy a cross-correlation property within the set of sequences 610-a,or have a level of correlation with a set of QPSK sequences, or acombination thereof.

FIG. 6B illustrates an example of a sequence table 600-b that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-b may beimplemented by one or more devices in accordance with aspects of thewireless communications systems 100 and 200. For example, the sequencetable 600-b may correspond to time domain sequences of length 6. In someexamples, a time domain sequence of length 6 in the sequence table 600-bmay be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 600-b may include a set of sequences 610-b, each ofwhich may have a length (e.g., a length of 6). Each sequence 610-b maycorrespond to a particular index value of index 605-b in the sequencetable 600-b. In the sequence table 600-b, the index values may rangefrom a first value (e.g., 0) to a second value (e.g., 29). Withreference to FIG. 2, the base station 105-a may inform the UE 115-a ofan index value corresponding to a sequence to use for generation of thereference signal 215. The sequence may be defined by the followingexpression in some cases:

${{x(n)} = e^{\frac{j\;{\phi{(n)}}}{8}}},$where n=0, 1, . . . 5, and ϕ corresponds to at least one of thesequences in the set of sequences 610-b. For example, an index value of“0,” for example, may correspond to a sequence of [−7 7 7 −5 3 −1] inthe sequence table 600-b. The sequence table 600-b may satisfy one ormore of criteria (e.g. as described in FIG. 2). For example, eachsequence in the set of sequences 610-b may be unique, or satisfy acyclic auto-correlation property, or satisfy a cross-correlationproperty within the set of sequences 610-b, or have a level ofcorrelation with a set of QPSK sequences, or a combination thereof.

FIG. 6C illustrates an example of a sequence table 600-c that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-c may correspond totime domain 8PSK sequences of length 6. In some examples, the sequencetable 600-c may be implemented by one or more devices in accordance withaspects of the wireless communications systems 100 and 200. For example,the sequence table 600-c may correspond to time domain sequences oflength 6. In some examples, a time domain sequence of length 6 in thesequence table 600-c may be used to generate a reference signal asdescribed in FIGS. 1 through 5.

The sequence table 600-c may include a set of sequences 610-c, each ofwhich may have a length (e.g., a length of 6). Each sequence 610-c maycorrespond to a particular index value of index 605-c in the sequencetable 600-c. In the sequence table 600-c, the index values may rangefrom a first value (e.g., 0) to a second value (e.g., 29). Withreference to FIG. 2, the base station 105-a may inform the UE 115-a ofan index value corresponding to a sequence to use for generation of thereference signal 215.

The sequence may be defined by the following expression in some cases:

${{x(n)} = e^{\frac{j\;{\phi{(n)}}}{8}}},$where n=0, 1, . . . 5, and ϕ corresponds to at least one of thesequences in the set of sequences 610-c. For a given 8PSK sequence x(n)in the sequence table 600-c, both x and its time division (TD)orthogonal complementary coded (OCC) (TD-OCC) version x′ may have apeak-to-average-power ratio (PAPR) that is below a target threshold(e.g., a threshold PAPR). For example, a PAPR threshold may be 2 dB. Insome examples, for an 8PSK sequence x_((n))=x₁, x₂, x₃, x₄, x_(s), x₆,the TD-OCC version is x′_((n))=x₂, x₃, −x₄, −x_(s), −x₆. For example, inthe sequence table 600-c, an index value of “0,” for example, maycorrespond to a sequence of [−7 −5 5 1 −5 −1], which may correspond tothe following 8PSK sequence of length

${{6x_{(n)}} = \left\lbrack {e^{- \frac{j\; 7\pi}{8}},e^{- \frac{j\; 5\pi}{8}},e^{\frac{j\; 5\pi}{8}},e^{\frac{j\;\pi}{8}},e^{\frac{{- j}\; 5\pi}{8}},e^{- \frac{{- j}\;\pi}{8}}} \right\rbrack},$and the TD-OCC version may be

${x_{(n)}^{\prime} = \left\lbrack {e^{- \frac{j\; 7\pi}{8}},e^{- \frac{j\; 5\pi}{8}},e^{\frac{j\; 5\pi}{8}},{- e^{\frac{j\;\pi}{8}}},{- e^{\frac{{- j}\; 5\pi}{8}}},{- e^{- \frac{{- j}\;\pi}{8}}}} \right\rbrack},$As defined herein, the notation x(n) (e.g., x(1), x(2), x(3), . . . )and x_((n)) (e.g., x₁, x₂, x₃, . . . ) are identical and denote elementsof a vector x.

The sequence table 600-c may satisfy one or more of criteria (e.g. asdescribed in FIG. 2). For example, each sequence in the set of sequences610-c may be unique, or satisfy a cyclic auto-correlation property, orsatisfy a cross-correlation property within the set of sequences 610-c,or have a level of correlation with a set of QPSK sequences, or acombination thereof.

In some examples, the correlation between x and the TD-OCC version x′,and the correlation between x and the +1 cyclically shifted version ofx′, and the correlation between x and −1 shifted version of x′ may bebound by a threshold (e.g., all bounded below a second threshold target(e.g., a cross-correlation threshold)). By way of example, the +1cyclically shifted version of x′ is [x₂, x₃, −x₄, −x_(s), −x₆, x₁], andthe −1 cyclically shifted version of x′ is [x₂, x₃, −x₄, −x₅, −x₆, x₁].The correlation property explained above may be defined by the followingexpressionsΣ_(i=1) ⁶ x _(i) ·x _(i)*=0  (5)x ₁ ·x ₂ *+x ₂ ·x ₃ *+x ₃·(−x ₄)*+x ₄·(−x ₅)*+x ₅−(−x ₆)*+x ₆ ·x₁≤2  (6)x ₁·(−x ₆)*+x ₂ ·x ₁ *+x ₃ ·x ₂ *+x ₄ ·x ₃ *+x ₅·(−x ₄)*+x ₆·(−x₅)*≤2  (7)where x_(i)* denotes the complex conjugate of x_(i). In an example, withreference to expressions (5) through (7), the second threshold target(i.e., the cross-correlation threshold) may be 2. In some examples, forany pair of sequences x and y in the sequence table 600-c, the crosscorrelation between the sequences x and y, and the cross correlationbetween the sequences x and y′ (i.e., the TD-OCC version of y), betweenx and +1 and −1 cyclically-shifted version of y, between x and +1 and −1cyclically-shifted version of y′ may be bound by a threshold (e.g., allmay be bounded by a third threshold (e.g., a second cross-correlationthreshold). The cross-correlation may be defined according to the aboveexpressions.

FIG. 6D illustrates an example of a sequence table 600-d that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-d may correspond totime domain 8PSK sequences of length 6. In some examples, the sequencetable 600-d may be implemented by one or more devices in accordance withaspects of the wireless communications systems 100 and 200. For example,the sequence table 600-d may correspond to time domain sequences oflength 6. In some examples, a time domain sequence of length 6 in thesequence table 600-d may be used to generate a reference signal asdescribed in FIGS. 1 through 5.

The sequence table 600-d may include a set of sequences 610-d, each ofwhich may have a length (e.g., a length of 6). Each sequence 610-d maycorrespond to a particular index value of index 605-d in the sequencetable 600-d. In the sequence table 600-d, the index values may rangefrom a first value (e.g., 0) to a second value (e.g., 29). Withreference to FIG. 2, the base station 105-a may inform the UE 115-a ofan index value corresponding to a sequence to use for generation of thereference signal 215.

The sequence may be defined by the following expression in some cases.

${x_{(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . 5, and 0 corresponds to at least one of thesequences in the set of sequences 610-d. In some examples, for a given8PSK sequence x_((n))=x₁, x₂, x₃, x₄, x₅, x₆ in the sequence table600-d, one or more sequences having a length of 12 may be generated. Forexample, for an 8PSK sequence x_((n))=x₁, x₂, x₃, x₄, x₅, x₆ in thesequence table 600-d, the following four expressions (8) through (11)may be used to generate four sequence having a length of 12:a=[x,x]=[x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x ₆ ,x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x₆]  (8)b=[x ₁ ,x ₂ ,x ₃ ,−x ₄ ,−x ₅ ,−x ₆ ,x ₁ ,x ₂ ,x ₃ ,−x ₄ ,−x ₅ ,−x₆]  (9)c=[x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x ₆ ,−x ₁ ,−x ₂ ,−x ₃ ,−x ₄ ,−x ₅ ,−x₆]  (10)d=[x ₁ ,x ₂ ,x ₃ ,−x ₄ ,−x ₅ ,−x ₆ ,−x ₁ ,−x ₂ ,−x ₃ ,x ₄ ,x ₅ ,x₆]  (11)

The four generated sequences according to expressions (8) through (11)may be associated with a PAPR threshold. For example, for a givensequence (or each sequence) generated by the expressions (8) through(11) the PAPR threshold may be lower than 2.1 dB. In some examples, oneor more (or each) sequence in the sequence table 600-d may be used as abase sequence to generate multiple demodulation reference signal (DMRS)sequences, which may correspond to one or more DMRS ports. For example,expressions (8) through (11) can be used to generate four orthogonalDMRS sequences (of length 12) corresponding to four DMRS ports from abase sequence x (of length 6). As such, for each base sequence in thesequence table 600-d, all generated DMRS sequences based in part onexpressions (8) through (11) have a PAPR below a target PAPR threshold.

The sequence table 600-d may satisfy one or more of criteria (e.g. asdescribed in FIG. 2). For example, each sequence in the set of sequences610-d including the set of sequences (8) through (11) generated for agiven sequence in the sequence table 600-d may be unique, or satisfy acyclic auto-correlation property, or satisfy a cross-correlationproperty within the set of sequences 610-d or the set of sequences (8)through (11) generated for a given sequence in the sequence table 600-d,or have a level of correlation with a set of QPSK sequences, or acombination thereof. For example, each sequence in the set of sequences610-d including the set of sequences (8) through (11) generated for agiven sequence in the sequence table 600-d may satisfy thecross-correlation defined according to the above expressions (5) through(7).

FIG. 6E illustrates an example of a sequence table 600-e that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-e may correspond totime domain 8PSK sequences of length 6. In some examples, the sequencetable 600-e may be implemented by one or more devices in accordance withaspects of the wireless communications systems 100 and 200. For example,the sequence table 600-e may correspond to time domain sequences oflength 6. In some examples, a time domain sequence of length 6 in thesequence table 600-e may be used to generate a reference signal asdescribed in FIGS. 1 through 5.

The sequence table 600-e may include a set of sequences 610-e, each ofwhich may have a length (e.g., a length of 6). Each sequence 610-e maycorrespond to a particular index value of index 605-e in the sequencetable 600-e. The index values may range from a first value (e.g., 0) toa second value (e.g., 29). With reference to FIG. 2, the base station105-a may inform the UE 115-a of an index value corresponding to asequence to use for generation of the reference signal 215.

A sequence may be defined by the following expression in some cases:

${x_{(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . 5, and ϕ relates to at least one of the sequences inthe set of sequences 610-e. In some examples, for a given 8PSK sequencex_((n))=[x₁, x₂, x₃, x₄, x₅, x₆] in the sequence table 600-e, one ormore sequences having a length of 12 may be generated. For example, foran 8PSK sequence x_((n))=[x₁, x₂, x₃, x₄, x₅, x₆] in the sequence table600-e, expressions (12) and (13) may be used to generate sequenceshaving a length of 12.

$\begin{matrix}{\mspace{79mu}{a = {\left\lbrack {x,x} \right\rbrack = \left\lbrack {x_{1},x_{2},x_{3},x_{4},x_{5},x_{6},x_{1},x_{2},x_{3},x_{4},x_{5},x_{6}} \right\rbrack}}} & (12) \\{b = \left\lbrack {x_{1},{x_{2}e^{\frac{j*2\;\pi}{12}}},{x_{3}e^{\frac{2j*2\pi}{12}}},{x_{4}e^{\frac{3j*2\pi}{12}}},{x_{5}e^{\frac{4j*2\pi}{12}}},{x_{6}e^{\frac{5j*2\pi}{12}}},{x_{1}e^{\frac{6j*2\;\pi}{12}}},{x_{2}e^{\frac{7j\; 2\;\pi}{12}}},{x_{3}e^{\frac{8j\; 2\;\pi}{12}}},{x_{4}e^{\frac{9j\; 2\pi}{12}}},{x_{5}e^{\frac{10j\; 2\pi}{12}}},{x_{6}e^{\frac{11j\; 2\pi}{12}}}} \right\rbrack} & (13)\end{matrix}$

In some examples, sequences generated according to expressions (12) and(13) may be associated with a PAPR threshold. In some examples, a PAPRfor a given sequence (or each sequence) generated by expressions (12)and (13) may be bound by a threshold, such as 2.05 dB, for example,after applying a frequency-domain spectrum shaping (FDSS) thatcorresponds to a time-domain filter, such as a 3-tap filter [−0.28,1,−0.28] on the sequence generated by (12) and (13). The sequence table600-e may satisfy one or more of criteria (e.g. as described in FIG. 2).For example, sequences generated according to expressions (12) and (13)for a given sequence in the sequence table 600-e may be unique, orsatisfy a cyclic auto-correlation property, or satisfy across-correlation property, or have a level of correlation with a set ofQPSK sequences, or a combination thereof. For example, sequencesgenerated according to expressions (12) and (13) for a given sequence inthe sequence table 600-e may satisfy the cross-correlation definedaccording to the above expressions (5) through (7).

In some examples, one or more sequences in the sequence table 600-e maybe used as a base sequence to generate multiple DMRS sequences, whichmay correspond to one or more DMRS ports. For example, (12) and (13) canbe used to generate two orthogonal DMRS sequences (of length 12)corresponding to two DMRS ports from a base sequence x (of length 6).Therefore, each sequence generated according to (12) and (13) maycorrespond to a DMRS sequence, which may correspond to a DMRS port on anuplink resource. For example, for an 8PSK sequence x_((n))=[x₁, x₂, x₃,x₄, x₅, x₆] in the sequence table 600-e, each sequence generatedaccording to (12) and (13) may correspond to a DMRS sequence of a DMRSport on an uplink resource. The two DMRS sequences (generated accordingto (12) and (13)) may be transmitted, for example, from two UEsrespectively in an uplink-multi-user MIMO transmission. In someexamples, DMRS sequences associated with each sequence of the sequences610-e in the sequence table 600-e may satisfy a PAPR, anauto-correlation property, or a cross-correlation property, or anycombination thereof.

FIG. 6F illustrates an example of a sequence table 600-f that supportscomputer-generated sequence design for

${x_{(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 600-f may correspond totime domain 8PSK sequences of length 6. In some examples, the sequencetable 600-f may be implemented by one or more devices in accordance withaspects of the wireless communications systems 100 and 200. For example,the sequence table 600-f may correspond to time domain sequences oflength 6. In some examples, a time domain sequence of length 6 in thesequence table 600-f may be used to generate a reference signal asdescribed in FIGS. 1 through 5.

A sequence may be defined by the following expression in some cases

$\frac{\pi}{2}$where n=0, 1, . . . 5, and ϕ relates to at least one of the sequences inthe set of sequences 610-f. In some examples, for a given 8PSK sequencex_((n))=[x₁, x₂, x₃, x₄, x₅, x₆] in the sequence table 600-f, one ormore sequences having a length of 12 may be generated. For example, foran 8PSK sequence x_((n))=[x₁, x₂, x₃, x₄, x₅, x₆] in the sequence table600-f, expressions (14) and (15) may be used to generate sequenceshaving a length of 12. Sequences generated according to expressions (14)and (15) may be associated with a PAPR threshold. In some examples, aPAPR for a given sequence (or each sequence) generated by expressions(14) and (15) may be upper-bounded by a threshold, such as 2.05 dB, forexample, after applying an FDSS that corresponds to a time-domainfilter, such as a 3-tap filter [−0.28,1,−0.28] on the sequence generatedby (14) and (15).a=[x,x]=[x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x ₆ ,x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x₆]  (14)b=[x ₁ ,x ₂ ,x ₃ ,x ₄ ,x ₅ ,x ₆ ,−x ₁ ,−x ₂ ,−x ₃ ,−x ₄ ,−x ₅ ,−x₆]  (15)

In some examples, the sequence table 600-f may satisfy one or more ofcriteria (e.g. as described in FIG. 2). For example, sequences generatedaccording to expressions (14) and (15) for a given sequence in thesequence table 600-f may be unique, or satisfy a cyclic auto-correlationproperty, or satisfy a cross-correlation property, or have a level ofcorrelation with a set of QPSK sequences, or a combination thereof. Forexample, sequences generated according to expressions (14) and (15) fora given sequence in the sequence table 600-f may satisfy thecross-correlation defined according to the above expressions (5) through(7).

One or more (or each) sequence(s) in the sequence table 600-f may beused as a base sequence to generate multiple DMRS sequences, which maycorrespond to one or more DMRS ports. For example, (14) and (15) can beused to generate two orthogonal DMRS sequences (of length 12)corresponding to two DMRS ports from a base sequence x (of length 6).Therefore, each sequence generated according to (14) and (15) maycorrespond to a DMRS sequence, which may correspond to a DMRS port on anuplink resource. For example, for a sequence in the sequence table600-f, each sequence generated according to (14) and (15) may correspondto a DMRS sequence of a DMRS port on an uplink resource. The two DMRSsequences (generated according to (14) and (15)) may be transmitted, forexample, from two UEs respectively in an uplink-multi-user MIMOtransmission. In some examples, DMRS sequences associated with eachsequence of the sequences 610-f in the sequence table 600-f may alsosatisfy a PAPR, an auto-correlation property, or a cross-correlationproperty, or any combination thereof, as described above.

FIG. 7 illustrates an example of a sequence table 700 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 700 may be implementedby one or more devices in accordance with aspects of the wirelesscommunications systems 100 and 200. For example, the sequence table 700may correspond to frequency domain 8PSK sequences of length 6. In someexamples, a frequency domain sequence of length 6 in the sequence table700 may be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 700 may include a set of sequences 710, each of whichmay have a length (e.g., a length of 6). Each sequence 710 maycorrespond to a particular index value of index 705 in the sequencetable 700. In the sequence table 700, the index values may range from afirst value (e.g., 0) to a second value (e.g., 29). With reference toFIG. 2, the base station 105-a may inform the UE 115-a of an index valuecorresponding to a sequence to use for generation of the referencesignal 215. The sequence may be defined by the following expression:

${{x(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . 5, and ϕ corresponds to at least one of thesequences in the set of sequences 710. For example, an index value of“14,” for example, may correspond to a sequence of [−7 −1 −7 3 5 −7] inthe sequence table 700. The sequence table 700 may satisfy one or moreof the criteria as described in FIG. 2. For example, each sequence inthe set of sequences 710 may be unique, or satisfy a cyclicauto-correlation property, or satisfy a cross-correlation propertywithin the set of sequences 710, or have a level of correlation with aset of QPSK sequences, or a combination thereof.

FIG. 8 illustrates an example of a sequence table 800 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 800 may be implementedby one or more devices in accordance with aspects of the wirelesscommunications systems 100 and 200. For example, the sequence table 800may correspond to frequency domain 8PSK sequences of length 12. In someexamples, a frequency domain sequence of length 12 in the sequence table800 may be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 800 may include a set of sequences 810, each of whichmay have a length (e.g., a length of 12). Each sequence 810 maycorrespond to a particular index value of index 805 in the sequencetable 800. In the sequence table 800, the index values may range from afirst value (e.g., 0) to a second value (e.g., 29). With reference toFIG. 2, the base station 105-a may inform the UE 115-a of an index valuecorresponding to a sequence to use for generation of the referencesignal 215. The sequence may be defined by the following expression:

${{x(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . 11, and ϕ corresponds to at least one of thesequences in the set of sequences 810. The sequence table 800 maysatisfy one or more of the criteria as described in FIG. 2. For example,each sequence in the set of sequences 810 may be unique, or satisfy acyclic auto-correlation property, or satisfy a cross-correlationproperty within the set of sequences 810, or have a level of correlationwith a set of QPSK sequences, or a combination thereof.

FIG. 9 illustrates an example of a sequence table 900 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 900 may be implementedby one or more devices in accordance with aspects of the wirelesscommunications systems 100 and 200. For example, the sequence table 900may correspond to frequency domain 8PSK sequences of length 18. In someexamples, a frequency domain sequence of length 18 in the sequence table900 may be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 900 may include a set of sequences 910, each of whichmay have a length (e.g., a length of 18). Each sequence 910 maycorrespond to a particular index value of index 905 in the sequencetable 900. In the sequence table 900, the index values may range from afirst value (e.g., 0) to a second value (e.g., 29). With reference toFIG. 2, the base station 105-a may inform the UE 115-a of an index valuecorresponding to a sequence to use for generation of the referencesignal 215. The sequence may be defined by the following expression:

${{x(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . , 17, and ϕ corresponds to at least one of thesequences in the set of sequences 910. The sequence table 900 maysatisfy one or more of the criteria as described in FIG. 2. For example,each sequence in the set of sequences 910 may be unique, or satisfy acyclic auto-correlation property, or satisfy a cross-correlationproperty within the set of sequences 910, or have a level of correlationwith a set of QPSK sequences, or a combination thereof.

FIG. 10 illustrates an example of a sequence table 1000 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. In some examples, the sequence table 1000 may be implementedby one or more devices in accordance with aspects of the wirelesscommunications systems 100 and 200. For example, the sequence table 1000may correspond to frequency domain sequences of length 24. In someexamples, a frequency domain sequence of length 24 in the sequence table1000 may be used to generate a reference signal as described in FIGS. 1through 5.

The sequence table 1000 may include a set of sequences 1010, each ofwhich may have a length (e.g., a length of 24). Each sequence 1010 maycorrespond to a particular index value of index 1005 in the sequencetable 1000. In the sequence table 1000, the index values may range froma first value (e.g., 0) to a second value (e.g., 29). With reference toFIG. 2, the base station 105-a may inform the UE 115-a of an index valuecorresponding to a sequence to use for generation of the referencesignal 215. The sequence may be defined by the following expression:

${{x(n)} = e^{\frac{j\;{\varnothing{(n)}}}{8}}},$where n=0, 1, . . . , 23, and ϕ corresponds to at least one of thesequences in the set of sequences 1010. The sequence table 1000 maysatisfy one or more of the criteria as described in FIG. 2. For example,each sequence in the set of sequences 1010 may be unique, or satisfy acyclic auto-correlation property, or satisfy a cross-correlationproperty within the set of sequences 1010, or have a level ofcorrelation with a set of QPSK sequences, or a combination thereof.

It is noted that the sequence tables 600, 700, 800, 900, and 1000 areexamples, and that other sequence tables may be used instead of or inaddition to the listed sequences.

FIG. 11 shows a block diagram 1100 of a device 1105 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The device 1105 may be an example of aspects of a device asdescribed herein. The device 1105 may include a receiver 1110, acommunications manager 1115, and a transmitter 1120. The device 1105 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related tocomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data, etc.). Information may be passed on to othercomponents of the device 1105. The receiver 1110 may be an example ofaspects of the transceiver 1420 described with reference to FIG. 14. Thereceiver 1110 may utilize a single antenna or a set of antennas.

The communications manager 1115 may identify a sequence lengthcorresponding to a number of resource blocks, select a modulation schemebased on the sequence length. The communications manager 1115 may alsoselect, from a set of sequences associated with the modulation scheme, asequence having the sequence length, where the set of sequences includesat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences. The communications manager 1115 maygenerate a reference signal for a data transmission based on thesequence, and transmit the reference signal within the number ofresource blocks.

The communications manager 1115 may also receive a control messageincluding an indication of a number of resource blocks associated with areference signal, and receive the reference signal for a datatransmission within the number of resource blocks, where the referencesignal is generated based on a sequence having the sequence length. Thecommunications manager 1115 may identify a sequence length correspondingto the number of resource blocks based on the control message, where thesequence is from a set of sequences including at least one of a set oftime domain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences, anddemodulate the reference signal based on a modulation scheme associatedwith the sequence length. The communications manager 1115 may be anexample of aspects of the communications manager 1410 described herein.

The communications manager 1115, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1115, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 1115, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1115, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1115, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The transmitter 1120 may transmit signals generated by other componentsof the device 1105. In some examples, the transmitter 1120 may becollocated with a receiver 1110 in a transceiver module. For example,the transmitter 1120 may be an example of aspects of the transceiver1420 described with reference to FIG. 14. The transmitter 1120 mayutilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a device 1205 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The device 1205 may be an example of aspects of a device1105 or a UE 115 as described herein. The device 1205 may include areceiver 1210, a communications manager 1215, and a transmitter 1245.The device 1205 may also include a processor. Each of these componentsmay be in communication with one another (e.g., via one or more buses).

The receiver 1210 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related tocomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data, etc.). Information may be passed on to othercomponents of the device 1205. The receiver 1210 may be an example ofaspects of the transceiver 1420 described with reference to FIG. 14. Thereceiver 1210 may utilize a single antenna or a set of antennas.

The communications manager 1215 may be an example of aspects of thecommunications manager 1115 as described herein. The communicationsmanager 1215 may include a sequence length component 1220, a modulationcomponent 1225, a sequence selection component 1230, a signal component1235, and a demodulation component 1240. The communications manager 1215may be an example of aspects of the communications manager 1410described herein.

The sequence length component 1220 may identify a sequence lengthcorresponding to a number of resource blocks. The sequence lengthcomponent 1220 may identify that the sequence length satisfies athreshold length, and select the set of time domain phase shift keyingcomputer-generated sequences or the set of frequency domain phase shiftkeying computer-generated sequences based at least in part on thesequence length satisfying the threshold. The sequence length component1220 may identify that the sequence length satisfies a threshold length,and select the set of frequency domain phase shift keyingcomputer-generated sequences based at least in part on the sequencelength satisfying the threshold. The sequence length component 1220 mayselect a time-domain sequence when the sequence length is a first valueor selecting a frequency-domain sequence when the sequence length is asecond value.

The modulation component 1225 may select a modulation scheme based onthe sequence length. The modulation component 1225 may select amodulation scheme based on the sequence length. The modulation component1225 may identify a set of modulation schemes, where each modulationscheme is for a different sequence length, where the different sequencelengths includes at least one of a sequence of length 6, a sequence oflength 12, a sequence of length 18, or a sequence of length 24, andidentify the modulation scheme associated with the sequence length inthe set of modulation schemes, where selecting the modulation scheme isfurther based at least in part on identifying the modulation schemeassociated with the sequence length in the set of modulation schemes.The modulation component 1225 may select a first modulation scheme whenthe sequence length is a first value or selecting a second modulationscheme when sequence length is a second value, where the firstmodulation scheme is different from the second modulation scheme. Forexample, the first modulation scheme may include an 8PSK sequence whenthe sequence length is a length of 6 and the second modulation schemeincludes a

$\frac{\pi}{2}$sequence when the sequence length is greater than the length of 6.

The sequence selection component 1230 may select, from a set ofsequences associated with the modulation scheme, a sequence having thesequence length, where the set of sequences includes at least one of aset of time domain phase shift keying computer-generated sequences or aset of frequency domain phase shift keying computer-generated sequences.The signal component 1235 may generate a reference signal for a datatransmission based on the sequence and transmit the reference signalwithin the number of resource blocks. The signal component 1235 mayreceive a control message including an indication of a number ofresource blocks associated with a reference signal and receive thereference signal for a data transmission within the number of resourceblocks, where the reference signal is generated based on a sequencehaving the sequence length.

The sequence length component 1220 may identify a sequence lengthcorresponding to the number of resource blocks based on the controlmessage, where the sequence is from a set of sequences including atleast one of a set of time domain phase shift keying computer-generatedsequences or a set of frequency domain phase shift keyingcomputer-generated sequences. The demodulation component 1240 maydemodulate the reference signal based on a modulation scheme associatedwith the sequence length.

The transmitter 1245 may transmit signals generated by other componentsof the device 1205. In some examples, the transmitter 1245 may becollocated with a receiver 1210 in a transceiver module. For example,the transmitter 1245 may be an example of aspects of the transceiver1420 described with reference to FIG. 14. The transmitter 1245 mayutilize a single antenna or a set of antennas.

FIG. 13 shows a block diagram 1300 of a communications manager 1305 thatsupports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The communications manager 1305 may be an example of aspectsof a communications manager 1115, a communications manager 1215, or acommunications manager 1410 described herein. The communications manager1305 may include a sequence length component 1310, a modulationcomponent 1315, a sequence selection component 1320, a signal component1325, and a demodulation component 1330. Each of these modules maycommunicate, directly or indirectly, with one another (e.g., via one ormore buses).

The sequence length component 1310 may identify a sequence lengthcorresponding to a number of resource blocks. In some examples, thesequence length component 1310 may identify a sequence lengthcorresponding to the number of resource blocks based on the controlmessage, where the sequence is from a set of sequences including atleast one of a set of time domain phase shift keying computer-generatedsequences or a set of frequency domain phase shift keyingcomputer-generated sequences. The sequence length component 1310 mayidentify that the sequence length satisfies a threshold length, andselect the set of time domain phase shift keying computer-generatedsequences or the set of frequency domain phase shift keyingcomputer-generated sequences based at least in part on the sequencelength satisfying the threshold. The sequence length component 1310 mayidentify that the sequence length satisfies a threshold length, andselect the set of frequency domain phase shift keying computer-generatedsequences based at least in part on the sequence length satisfying thethreshold. The sequence length component 1310 may select a time-domainsequence when the sequence length is a first value or selecting afrequency-domain sequence when the sequence length is a second value.

The modulation component 1315 may select a modulation scheme based onthe sequence length. In some examples, the modulation component 1315 maymodulate the data transmission using π/2 BPSK modulation to generate aπ/2 BPSK modulated data transmission. In some examples, the modulationcomponent 1315 may transmit the π/2 BPSK modulated data transmissionwithin the number of resource blocks, where a peak to average powerratio associated with the π/2 BPSK modulated data transmission is withina threshold of a peak to average power ratio associated with thereference signal. In some examples, the modulation component 1315 maymodulate the sequence using the modulation scheme, where generating thereference signal for the data transmission is further based on themodulating. The modulation component 1315 may identify a set ofmodulation schemes, where each modulation scheme is for a differentsequence length, where the different sequence lengths includes at leastone of a sequence of length 6, a sequence of length 12, a sequence oflength 18, or a sequence of length 24, and identify the modulationscheme associated with the sequence length in the set of modulationschemes, where selecting the modulation scheme is further based at leastin part on identifying the modulation scheme associated with thesequence length in the set of modulation schemes. The modulationcomponent 1315 may select a first modulation scheme when the sequencelength is a first value or selecting a second modulation scheme whensequence length is a second value. In some examples, the firstmodulation scheme includes an 8PSK sequence when the sequence length isa length of 6 and the second modulation scheme includes a

$\frac{\pi}{2}$sequence when me sequence length is greater than the length of 6.

The sequence selection component 1320 may select, from a set ofsequences associated with the modulation scheme, a sequence having thesequence length, where the set of sequences includes at least one of aset of time domain phase shift keying computer-generated sequences or aset of frequency domain phase shift keying computer-generated sequences.In some examples, the sequence selection component 1320 may identify aset of sequence tables that each include a set of sequences for amodulation scheme and for a different sequence length. In some examples,the sequence selection component 1320 may identify, from the set ofsequence tables, a sequence table including the set of sequencesassociated with the sequence length and the modulation scheme, whereselecting the sequence is further based on identifying the sequencetable. In some examples, the sequence selection component 1320 mayselect a sequence that includes a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences.

The sequence selection component 1320 may generate a set of sequencetables that each include a set of sequences for a modulation scheme andfor a different sequence length. In some examples, the sequenceselection component 1320 may generate each sequence of the set ofsequences based on the equation

${{x(k)} = e^{j\;{\varnothing{(k)}}\frac{\pi}{8}}},$where k may be an integer value ranging from 0 to 5. In some examples, asequence length of each sequence of the set of sequences may be a lengthof 6, and each number in each sequence may have an integer valueselected from a set of integer values including −7, −5, −3, −1, 1, 3, 5,and 7. In some aspects, one or more sequence tables of the set ofsequence tables may include sequences [−7 −3 −7 −3 7 −5], [−7 −3 1 −5 −1−5], and [−7 −3 3 −3 −7 −5]. The sequence selection component 1320 mayidentify a set of sequence tables that each include a set of sequencesfor a modulation scheme and for a different sequence length. In someexamples, the sequence selection component 1320 may identify, from theset of sequence tables, a sequence table including the set of sequencesassociated with the sequence length and the modulation scheme, wheredemodulating the reference signal is further based on identifying thesequence table. In some examples, identifying a sequence that includes aset of time domain phase shift keying computer-generated sequences or aset of frequency domain phase shift keying computer-generated sequences.

The signal component 1325 may generate a reference signal for a datatransmission based on the sequence. In some examples, the signalcomponent 1325 may transmit the reference signal within the number ofresource blocks. In some examples, the signal component 1325 may receivea control message including an indication of a number of resource blocksassociated with a reference signal. In some examples, the signalcomponent 1325 may receive the reference signal for a data transmissionwithin the number of resource blocks, where the reference signal isgenerated based on a sequence having the sequence length.

The demodulation component 1330 may demodulate the reference signalbased on a modulation scheme associated with the sequence length. Insome examples, the demodulation component 1330 may demodulate the datatransmission using a π/2 BPSK modulation scheme to generate a π/2 BPSKdemodulated data transmission, where a peak to average power ratioassociated with the π/2 BPSK demodulated data transmission is within athreshold of a peak to average power ratio associated with the referencesignal.

FIG. 14 shows a diagram of a system 1400 including a device 1405 thatsupports computer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The device 1405 may be an example of or include thecomponents of device 1105, device 1205, or a device as described herein.The device 1405 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 1410, an I/Ocontroller 1415, a transceiver 1420, an antenna 1425, memory 1430, and aprocessor 1440. These components may be in electronic communication viaone or more buses (e.g., bus 1445).

The communications manager 1410 may identify a sequence lengthcorresponding to a number of resource blocks, select a modulation schemebased on the sequence length, select, from a set of sequences associatedwith the modulation scheme, a sequence having the sequence length, wherethe set of sequences includes at least one of a set of time domain phaseshift keying computer-generated sequences or a set of frequency domainphase shift keying computer-generated sequences, generate a referencesignal for a data transmission based on the sequence, and transmit thereference signal within the number of resource blocks. Thecommunications manager 1410 may also receive a control message includingan indication of a number of resource blocks associated with a referencesignal, receive the reference signal for a data transmission within thenumber of resource blocks, where the reference signal is generated basedon a sequence having the sequence length, identify a sequence lengthcorresponding to the number of resource blocks based on the controlmessage, where the sequence is from a set of sequences including atleast one of a set of time domain phase shift keying computer-generatedsequences or a set of frequency domain phase shift keyingcomputer-generated sequences, and demodulate the reference signal basedon a modulation scheme associated with the sequence length.

The I/O controller 1415 may manage input and output signals for thedevice 1405. The I/O controller 1415 may also manage peripherals notintegrated into the device 1405. In some cases, the I/O controller 1415may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1415 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1415may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1415may be implemented as part of a processor. In some cases, a user mayinteract with the device 1405 via the I/O controller 1415 or viahardware components controlled by the I/O controller 1415.

The transceiver 1420 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1420 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1420 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas. In some cases, the device1405 may include a single antenna 1425. However, in some cases thedevice 1405 may have more than one antenna 1425, which may be capable ofconcurrently transmitting or receiving multiple wireless transmissions.

The memory 1430 may include RAM and ROM. The memory 1430 may storecomputer-readable, computer-executable code 1435 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 1430 may contain, amongother things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

The processor 1440 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1440 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1440. The processor 1440 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1430) to cause the device 1405 to perform variousfunctions (e.g., functions or tasks supporting computer-generatedsequence design for

$\frac{\pi}{2}$BPSK modulation data).

The code 1435 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1435 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1435 may not be directly executable by theprocessor 1440 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 15 shows a flowchart illustrating a method 1500 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The operations of method 1500 may be implemented by a deviceor its components as described herein. For example, the operations ofmethod 1500 may be performed by a communications manager as describedwith reference to FIGS. 11 through 14. In some examples, a device mayexecute a set of instructions to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, a device may perform aspects of the functions describedbelow using special-purpose hardware.

At 1505, the device may identify a sequence length corresponding to anumber of resource blocks. The operations of 1505 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1505 may be performed by a sequence length componentas described with reference to FIGS. 11 through 14.

At 1510, the device may select a modulation scheme based on the sequencelength. The operations of 1510 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1510may be performed by a modulation component as described with referenceto FIGS. 11 through 14.

At 1515, the device may select, from a set of sequences associated withthe modulation scheme, a sequence having the sequence length, where theset of sequences includes at least one of a set of time domain phaseshift keying computer-generated sequences or a set of frequency domainphase shift keying computer-generated sequences. The operations of 1515may be performed according to the methods described herein. In someexamples, aspects of the operations of 1515 may be performed by asequence selection component as described with reference to FIGS. 11through 14.

At 1520, the device may generate a reference signal for a datatransmission based on the sequence. The operations of 1520 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1520 may be performed by a signal componentas described with reference to FIGS. 11 through 14.

At 1525, the device may transmit the reference signal within the numberof resource blocks. The operations of 1525 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1525 may be performed by a signal component as describedwith reference to FIGS. 11 through 14.

FIG. 16 shows a flowchart illustrating a method 1600 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The operations of method 1600 may be implemented by a deviceor its components as described herein. For example, the operations ofmethod 1600 may be performed by a communications manager as describedwith reference to FIGS. 11 through 14. In some examples, a device mayexecute a set of instructions to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, a device may perform aspects of the functions describedbelow using special-purpose hardware.

At 1605, the device may identify a sequence length corresponding to anumber of resource blocks. The operations of 1605 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1605 may be performed by a sequence length componentas described with reference to FIGS. 11 through 14.

At 1610, the device may identify a set of sequence tables that eachinclude a set of sequences for a modulation scheme and for a differentsequence length. The operations of 1610 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1610 may be performed by a sequence selection component asdescribed with reference to FIGS. 11 through 14.

At 1615, the device may identify, from the set of sequence tables, asequence table including the set of sequences associated with thesequence length and the modulation scheme, where selecting the sequenceis further based on identifying the sequence table. The operations of1615 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1615 may be performed by asequence selection component as described with reference to FIGS. 11through 14.

At 1620, the device may select a modulation scheme based on the sequencelength. The operations of 1620 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1620may be performed by a modulation component as described with referenceto FIGS. 11 through 14.

At 1625, the device may select, from a set of sequences associated withthe modulation scheme, a sequence having the sequence length, where theset of sequences includes at least one of a set of time domain phaseshift keying computer-generated sequences or a set of frequency domainphase shift keying computer-generated sequences. The operations of 1625may be performed according to the methods described herein. In someexamples, aspects of the operations of 1625 may be performed by asequence selection component as described with reference to FIGS. 11through 14.

At 1630, the device may generate a reference signal for a datatransmission based on the sequence. The operations of 1630 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1630 may be performed by a signal componentas described with reference to FIGS. 11 through 14.

At 1635, the device may transmit the reference signal within the numberof resource blocks. The operations of 1635 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1635 may be performed by a signal component as describedwith reference to FIGS. 11 through 14.

FIG. 17 shows a flowchart illustrating a method 1700 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The operations of method 1700 may be implemented by a deviceor its components as described herein. For example, the operations ofmethod 1700 may be performed by a communications manager as describedwith reference to FIGS. 11 through 14. In some examples, a device mayexecute a set of instructions to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, a device may perform aspects of the functions describedbelow using special-purpose hardware.

At 1705, the device may identify a sequence length corresponding to anumber of resource blocks. The operations of 1705 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1705 may be performed by a sequence length componentas described with reference to FIGS. 11 through 14.

At 1710, the device may select a modulation scheme based on the sequencelength. The operations of 1710 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1710may be performed by a modulation component as described with referenceto FIGS. 11 through 14.

At 1715, the device may select, from a set of sequences associated withthe modulation scheme, a sequence having the sequence length, where theset of sequences includes at least one of a set of time domain phaseshift keying computer-generated sequences or a set of frequency domainphase shift keying computer-generated sequences. The operations of 1715may be performed according to the methods described herein. In someexamples, aspects of the operations of 1715 may be performed by asequence selection component as described with reference to FIGS. 11through 14.

At 1720, the device may select a sequence that includes a set of timedomain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences. Forexample, the device may select a sequence that includes a set oftime-domain PSK symbols. The operations of 1720 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1720 may be performed by a sequence selectioncomponent as described with reference to FIGS. 11 through 14.

At 1725, the device may generate a reference signal for a datatransmission based on the sequence. The operations of 1725 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1725 may be performed by a signal componentas described with reference to FIGS. 11 through 14.

At 1730, the device may transmit the reference signal within the numberof resource blocks. The operations of 1730 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1730 may be performed by a signal component as describedwith reference to FIGS. 11 through 14.

FIG. 18 shows a flowchart illustrating a method 1800 that supportscomputer-generated sequence design for

$\frac{\pi}{2}$BPSK modulation data in accordance with aspects of the presentdisclosure. The operations of method 1800 may be implemented by a deviceor its components as described herein. For example, the operations ofmethod 1800 may be performed by a communications manager as describedwith reference to FIGS. 11 through 14. In some examples, a device mayexecute a set of instructions to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, a device may perform aspects of the functions describedbelow using special-purpose hardware.

At 1805, the device may identify a sequence length corresponding to anumber of resource blocks associated with a reference signal based on acontrol message, where the sequence is from a set of sequences includingat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences. The operations of 1805 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1805 may be performed by a sequence lengthcomponent as described with reference to FIGS. 11 through 14.

At 1810, the device may receive the reference signal for a datatransmission within the number of resource blocks, where the referencesignal is generated based on a sequence having the sequence length. Theoperations of 1810 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1810 may beperformed by a signal component as described with reference to FIGS. 11through 14.

At 1815, the device may demodulate the reference signal based on amodulation scheme associated with the sequence length. The operations of1815 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1815 may be performed by ademodulation component as described with reference to FIGS. 11 through14.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned herein as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell maybe associated with a lower-powered base station, as compared with amacro cell, and a small cell may operate in the same or different (e.g.,licensed, unlicensed, etc.) frequency bands as macro cells. Small cellsmay include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEshaving an association with the femto cell (e.g., UEs in a closedsubscriber group (CSG), UEs for users in the home, and the like). An eNBfor a macro cell may be referred to as a macro eNB. An eNB for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. An eNB may support one or multiple (e.g., two, three, four,and the like) cells, and may also support communications using one ormultiple component carriers.

The wireless communications systems described herein may supportsynchronous or asynchronous operation. For synchronous operation, thebase stations may have similar frame timing, and transmissions fromdifferent base stations may be approximately aligned in time. Forasynchronous operation, the base stations may have different frametiming, and transmissions from different base stations may not bealigned in time. The techniques described herein may be used for eithersynchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other non-transitory medium that can be used tocarry or store desired program code means in the form of instructions ordata structures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include CD, laser disc, optical disc,digital versatile disc (DVD), floppy disk and Blu-ray disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communications, comprising:identifying a sequence length corresponding to a number of resourceblocks; selecting a modulation scheme based at least in part on thesequence length, wherein the modulation scheme comprises an 8 phaseshift keying (8PSK) modulation scheme; selecting, from a set ofsequences associated with the modulation scheme, a sequence having thesequence length, wherein the set of sequences comprises at least one ofa set of time domain phase shift keying computer-generated sequences ora set of frequency domain phase shift keying computer-generatedsequences, wherein the set of time domain phase shift keyingcomputer-generated sequence comprises time domain 8PSK sequences oflength 6; generating a reference signal for a data transmission based atleast in part on the sequence; and transmitting the reference signalwithin the number of resource blocks.
 2. The method of claim 1, whereinthe data transmission comprises a π/2 phase shift keying modulated datatransmission.
 3. The method of claim 1, wherein the data transmissioncomprises at least one of a physical uplink shared channel (PUSCH)transmission, a physical uplink control channel (PUCCH) transmission, aphysical downlink shared channel (PDSCH) transmission, a physicaldownlink control channel (PDCCH) transmission, a physical sidelinkshared channel (PSSCH) transmission, or a physical sidelink controlchannel (PSCCH) transmission.
 4. The method of claim 1, wherein the setof time domain phase shift keying computer-generated sequence comprisesat least one of time domain 8PSK sequences of length 12, time domain8PSK sequences of length 18, or time domain 8PSK sequences of length 24.5. The method of claim 1, wherein the set of frequency domain phaseshift keying computer-generated sequence comprises at least one offrequency domain 8PSK sequences of length 6, frequency domain 8PSKsequences of length 12, frequency domain 8PSK sequences of length 18, orfrequency domain 8PSK sequences of length
 24. 6. The method of claim 1,wherein selecting the modulation scheme comprises: selecting a firstmodulation scheme when the sequence length is a first value or selectinga second modulation scheme when sequence length is a second value. 7.The method of claim 1, further comprising: modulating the datatransmission using π/2 binary phase shift keying (BPSK) modulation togenerate a π/2 BPSK modulated data transmission; and transmitting theπ/2 BPSK modulated data transmission within the number of resourceblocks, wherein a peak to average power ratio associated with the π/2θBPSK modulated data transmission is within a threshold of a peak toaverage power ratio associated with the reference signal.
 8. The methodof claim 1, further comprising: generating a set of sequence tables thateach comprise a set of sequences for a modulation scheme and for adifferent sequence length, wherein generating each sequence of the setof sequences is based at least in part on the equation:x(k) =e^(Λ)(jϕ(k) π/8), wherein k is an integer value ranging from 0 to5, and a sequence length of each sequence of the set of sequences is alength of 6, each number in each sequence having an integer valueselected from a set of integer values comprising −7, −5, −3, −1, 1, 3,5, and
 7. 9. The method of claim 8, wherein one or more sequence tablesof the set of sequence tables comprises sequences [−7 −3 −7 −3 7 −5],[−7 −3 1 −5 −1 −5], and [−7 −3 3 −3 −7 −5].
 10. The method of claim 1,further comprising: identifying a set of sequence tables that eachcomprise a set of sequences for a modulation scheme and for a differentsequence length; and identifying, from the set of sequence tables, asequence table comprising the set of sequences associated with thesequence length and the modulation scheme, wherein selecting thesequence is further based at least in part on identifying the sequencetable.
 11. The method of claim 10, wherein each sequence table comprisesat least one of a set of time domain phase shift keyingcomputer-generated sequences or a set of frequency domain phase shiftkeying computer-generated sequences corresponding to a certain sequencelength.
 12. The method of claim 10, wherein each sequence in the set ofsequences is unique.
 13. The method of claim 10, wherein each sequencein the set of sequences satisfies a cyclic auto-correlation property.14. The method of claim 10, wherein each sequence in the set ofsequences satisfies a cross-correlation property within the set ofsequences.
 15. The method of claim 10, wherein the set of sequencescomprises a level of correlation with a set of quadrature phase shiftkeying (QPSK) sequences.
 16. The method of claim 15, wherein across-correlation between the set of sequences and the QPSK sequences islower than a threshold, wherein the set of sequences is associated witha first radio access technology and the QPSK sequences are associatedwith a second radio access technology different from the first radioaccess technology.
 17. The method of claim 1, wherein selecting thesequence comprises: selecting a sequence that comprises a set of timedomain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer- generated sequences. 18.The method of claim 1, further comprising: modulating the sequence usingthe modulation scheme, wherein generating the reference signal for thedata transmission is further based at least in part on the modulating.19. A method for wireless communications, comprising: identifying asequence length corresponding to a number of resource blocks; selectinga modulation scheme based at least in part on the sequence length byselecting a first modulation scheme when the sequence length is a firstvalue or selecting a second modulation scheme when sequence length is asecond value, wherein the first modulation scheme comprises an 8PSKsequence when the sequence length is a length of 6 and the secondmodulation scheme comprises a π/2 sequence when the sequence length isgreater than the length of 6; selecting, from a set of sequencesassociated with the modulation scheme, a sequence having the sequencelength, wherein the set of sequences comprises at least one of a set oftime domain phase shift keying computer-generated sequences or a set offrequency domain phase shift keying computer-generated sequences;generating a reference signal for a data transmission based at least inpart on the sequence; and transmitting the reference signal within thenumber of resource blocks.
 20. The method of claim 19, wherein thesequence length comprises a sequence of length 6, a sequence of length12, a sequence of length 18, or a sequence of length
 24. 21. The methodof claim 19, wherein selecting the sequence comprises: selecting atime-domain sequence when the sequence length is a first value orselecting a frequency-domain sequence when the sequence length is asecond value.
 22. An apparatus for wireless communications, comprising:a processor, memory in electronic communication with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to: identify a sequence length corresponding to anumber of resource blocks; select a modulation scheme based at least inpart on the sequence length, wherein the modulation scheme comprises an8 phase shift keying (8PSK) modulation scheme; select, from a set ofsequences associated with the modulation scheme, a sequence having thesequence length, wherein the set of sequences comprises at least one ofa set of time domain phase shift keying computer-generated sequences ora set of frequency domain phase shift keying computer-generatedsequences, wherein the set of time domain phase shift keyingcomputer-generated sequence comprises time domain 8PSK sequences oflength 6; generate a reference signal for a data transmission based atleast in part on the sequence; and transmit the reference signal withinthe number of resource blocks.
 23. The apparatus of claim 22, whereinthe instructions to select the modulation scheme are further executableby the processor to cause the apparatus to: select a first modulationscheme when the sequence length is a first value or select a secondmodulation scheme when sequence length is a second value.
 24. Theapparatus of claim 23, wherein the first modulation scheme comprises an8PSK sequence when the sequence length is a length of 6 and the secondmodulation scheme comprises a π/2 sequence when the sequence length isgreater than the length of 6.